Check for unused refdata values

Check for unused refdata values

Make a test using refdata fail if it does not produce some reference
values at all.  Use this instead of checkPresent() for some cases where
the new functionality is a clearer fit for the purpose.  It is possible
to trigger the check explicitly for a subtree, but if not done
otherwise, it is always done for all values at the end of the test.

Change-Id: I722abd978f0c8fa9dc279264ff90cdad02e02b9d